Did you test the “automatic language detection” feature with the default TwentyThirteen theme? Does it work with the default theme on your server but not with Enfold? Tbh I’m not aware of any theme code which might affect the automatic language detection and maybe it’s a general issue with your server/configuration.

I don’t know if it’s a theme or WPML plugin issue – that’s why I recommended to test the feature with the default TwentyThirteen theme. If the issue still exists with the default theme it’s a WPML issue for sure.